

Terry Pratchet wrote in Good Omens that the apocalypse horsemen Pestilence was slain by the advent of penicillin.
From my own head:
Mercury was killed to bring about the Internet.
Athena was not killed, but severely weakened to domesticate the herd animals.
We sacrificed Fenris for lap dogs.
I love this thread and will be working some of this into my next RPG storyline.
Likely, I get them confused.